Influence of temporal averaging in the performance of a rotating retarder imaging Stokes polarimeter

Lizana, Ángel; Campos, Juan; Eeckhout, Albert Van; Márquez, Andrés

doi:10.1364/oe.385623

Cited by 12 publications

(5 citation statements)

References 23 publications

(64 reference statements)

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“…The configuration and process of Stokes polarimeters using a rotating retarder with a fixed polarizer have been well established by various studies 41 – 43 . In the configuration shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

Optical monitoring of the plant growth status using polarimetry

Kim

Shin

Nam

et al. 2022

Sci Rep

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Polarimetry is a powerful characterization technique that uses a wealth of information from electromagnetic waves, including polarization. Using the rich information provided by polarimetry, it is being actively studied in biomedical fields such as cancer and tumor diagnosis. Despite its importance and potential in agriculture, polarimetry for living plants has not been well studied. A Stokes polarimetric imaging system was built to determine the correlation between the polarization states of the light passing through the leaf and the growth states of lettuce. The Stokes parameter s3 associated with circular polarization increased over time and was strongly correlated with the growth of lettuce seedlings. In the statistical analysis, the distribution of s3 followed the generalized extreme value (GEV) probability density function. Salt stress retarded plant growth, and the concentration of treated sodium chloride (NaCl) showed a negative correlation with the location parameter μ of GEV. The clear correlation reported here will open the possibility of polarization measurements on living plants, enabling real-time monitoring of plant health.

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Section: Methodsmentioning

confidence: 99%

Optical monitoring of the plant growth status using polarimetry

Kim

Shin

Nam

et al. 2022

Sci Rep

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“…Polarization measurement is important in many applications, such as in sky polarized light navigation [1], remote sensing [2][3][4], the food industry [5][6][7][8] and ellipsometry [9][10][11]. Generally, four methods, including interferometric polarimeter [12,13], temporally modulated polarimeter [14,15], division-of-amplitude polarimeter [16,17] and spatially modulated polarimeter [18][19][20][21], are well accepted to solve this problem. In a interferometric polarimeter, the coherent optical paths are constructed, and the polarization information can be calculated from the interference pattern.…”

Section: Introductionmentioning

confidence: 99%

An Improved CNN for Polarization Direction Measurement

Han,

Liu,

Wang

et al. 2023

Electronics

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Spatially polarization modulation has been proven to be an efficient and simple method for polarization measurement. Since the polarization information is encoded in the intensity distribution of the modulated light, the task of polarization measurement can be treated as the image processing problem, while the pattern of the light is captured by a camera. However, classical image processing methods could not meet the increasing demand of practical applications due to their poor computational efficiency. To address this issue, in this paper, an improved Convolutional Neural Network is proposed to extract the Stokes parameters of the light from the irradiance image. In our algorithm, residual blocks are adopted and different layers are connected to ensure that the underlying features include more details of the image. Furthermore, refined residual block and Global Average Pooling are introduced to avoid overfitting issues and gradient vanishing problems. Finally, our algorithm is tested on massive synthetic and real data, while the mean square error (MSE) between the extracted values and the true values of the normalized Stokes parameters is counted. Compared to VGG and FAM, the experimental results demonstrate that our algorithm has outstanding performance.

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“…Comparatively, the DoTP by rotating polarizer or retarder has good performances in terms of accuracy and sensitivity, except for dynamic property. Thus, some authors have moved back to the research of classic DoTP with a non-stop polarization modulator during polarization imaging, and the Stokes vector is resolved from captured images by utilizing temporal averaging or short integration time methods [28][29][30]. They prompt the development of the DoTP, and these methods bring about considerable improvement on the dynamic performance, while keeping its high accuracy.…”

Section: Introductionmentioning

confidence: 99%

Full-Stokes Retrieving and Configuration Optimization in a Time-Integration Imaging Polarimeter

Lian

Xiao

et al. 2022

Sensors

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A time-integration imaging polarimeter with continuous rotating retarder is presented, and its full-Stokes retrieving and configuration optimization are also demonstrated. The mathematical expression between the full-Stokes vector and the time-integration light intensities is derived. As a result, the state of polarization of incident light can be retrieved by only one matrix calculation. However, the modulation matrix deviates from the initial well-conditioned status due to time integration. Thus, we re-optimize the nominal angles for the special retardance of 132° and 90° with an exposure angle of 30°, which results in a reduction of 31.8% and 16.8% of condition numbers comparing to the original configuration, respectively. We also give global optimization results under different exposure angles and retardance of retarder; as a result, the 137.7° of retardance achieves a minimal condition number of 2.0, which indicates a well-conditioned polarimeter configuration. Besides, the frame-by-frame algorithm ensures the dynamic performance of the presented polarimeter. For a general brushless DC motor with a rotating speed of over 2000 rounds per minute, the speed of polarization imaging will achieve up to 270 frames per second. High precision and excellent dynamic performance, together with features of compactness, simplicity, and low cost, may give this traditional imaging polarimeter new life and attractive prospects.

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Influence of temporal averaging in the performance of a rotating retarder imaging Stokes polarimeter

Cited by 12 publications

References 23 publications

Optical monitoring of the plant growth status using polarimetry

Optical monitoring of the plant growth status using polarimetry

An Improved CNN for Polarization Direction Measurement

Full-Stokes Retrieving and Configuration Optimization in a Time-Integration Imaging Polarimeter

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